Process for gas incineration

Abstract

There is provided a process for the incineration of gases containing sulphur compounds by contacting these gases with an oxygen-containing gas in the presence of a catalyst composition comprising (i) a metal selected from bismuth, molybdenum and chromium as a first metal component and (ii) at least one Group IIA metal as a second metal component, supported on a refractory oxide carrier not being a carrier comprising both aluminum and phosphorus.

Description

BACKGROUND OF THE INVRNTIONThe present invention relates to a catalyst composition, to a process for its preparation and to its use in catalytic incineration of gases containing sulphur compounds, particularly hydrogen sulphide.The presence of hydrogen sulphide (H.sub.2 S) in process waste gases, which are released into the air, is bound to very stringent rules in most industrialised parts of the world. Waste gases containing H.sub.2 S are produced in many different processes, such as, for instance, in the well-known Claus process. This Claus process produces an effluent which may contain over 5% by volume of H.sub.2 S in addition to other sulphur compounds. A known method for reducing the level of sulphur compounds and H.sub.2 S in the Claus off-gas is, for instance, subjecting this off-gas to a catalytic reduction treatment, thereby converting the sulphur compounds present into H.sub.2 S, and subsequently removing the bulk of H.sub.2 S by an absorption treatment using a suitable H...

AI Technical Summary

Problems solved by technology

The occurrence of H.sub.2 oxidation is undesired, because the heat generated in this exothermic reaction may lead to a thermal run away reaction.

Furthermore, the H.sub.2 oxidation may also trigger other undesired reactions, such as the conversion of CO into COS and the (thermal) conversion of hydrocarbons.

Using the first metal component in amounts lower than 0.5% by weight is possible, but will normally not result in a sufficiently high catalytic activity.

On the other hand, applying amounts of more than 10% by weight will not result in a substantially improved catalytic performance and is also less preferred from a cost perspective.

At higher levels, additional preceding absorption treatments or combined reduction and absorption treatments are normally required in order to avoid the generation of too much heat in the exothermic incineration reaction, thus making the incineration ineffective from both an economic and a processing perspective.